Guitars generally consist of a body and an elongated neck and a plurality of strings, which are tensioned between a headstock at one end of the neck and a bridge, which is attached to the guitar body. In an acoustical guitar, the guitar body consists of spaced panels, including a body face panel, a body back panel and body side panels, which define a resonance chamber to provide the instrument with a desired tonal qualities.
The rigid attachment of the neck to the body and the size of the body causes the guitar to be relatively large and cumbersome to handle, transport and store. However, the need for strength within the body and neck to allow the guitar strings to be tensioned, and the requirement for the resonant chamber of the body has dictated acoustical guitar construction and bulk. A number of inventions have considered guitar constructions, which attempt to reduce the bulk of guitars for transportation and storage purposes. Examples of such inventions can be found in U.S. Pat. Nos. 4,073,211; 4,111,093; 4,433,603; 4,686,882; and 5,058,479. Many of these prior art collapsible guitars still result in a bulky size and require special carrying cases and special care when transporting. Others are more compact and are easily transportable. However, in order to provide such compactability, these guitars sacrifice acoustic performance.
U.S. Pat. No. 4,573,391, which issued to and is commonly owned by the applicant of the present invention, discloses an inflatable knock-down guitar, which overcame many of the deficiencies found in many of the prior art knock-down guitar patents. This reference teaches a knock-down guitar, which can be utilized in either an acoustic or electric mode, and which includes a plurality of guitar components that disassemble in such a manner as to permit the instrument to be placed within a conventional suitcase, thus eliminating the need for special carrying cases.
The '391 patent teaches that an inflatable bladder can be utilized as a resonance chamber for the guitar system disclosed therein when it is used in its acoustical mode. This guitar system, which is known as the CHRYSALIS.TM. Universal Guitar System, includes a family of interchangeable guitar components, which provides a number of features including: the ability of a guitarist to break down a full-size, full-function electric guitar to a shirt box size package for transport and to re-assemble the instrument to playing condition in a minimal time period, including the re-tuning and re-tuning of the guitar strings; allowing the same electric guitar to be quickly and easily converted to a full-size, full-function acoustic guitar by attaching an inflatable acoustic chamber to the guitar body; allowing a musician to easily and quickly make a variety of significant alterations to the guitar's quality or function by providing a plurality of separately available interchangeable components, including, headstocks, necks, body panels and bridges.
The advantages of the CHRYSALIS.TM. guitar system include the ability to assemble the instrument in any configuration and to maintain that configuration entirely by string tension. Furthermore, the CHRYSALIS.TM. guitar system teaches that all system components can be manufactured out of injection molded plastics common carbon fiber composites or lightweight metals, which allows a wide range of system performance characteristics and associated price ranges. Additionally, with the CHRYSALIS.TM. guitar system, all action, neck, and intonation adjustments could be made with three easily accessible set screws at the junction of the CHRYSALIS.TM. guitar's neck and body.
However, perhaps the most significant advance taught by the CHRYSALIS.TM. guitar system is the use of a new type of acoustic sound board analogue composed of a carbon fiber composite grillwork, which, in the CHRYSALIS.TM. guitar's acoustic mode supports a polymer membrane under tension.
One embodiment of a prior art modular guitar system 1 is shown in FIG. 1. Guitar 1 consists of a guitar body 2, a guitar neck 4, a headstock 6, bridge 8 and a plurality of strings (not shown). The strings are attached to the bridge 8 at one end and, at the headstock, the strings are attached to individual guitar string tuning machines 12.
The prior art guitar body 2 includes a face panel 14 consisting of first and second face panel sections 14A and 14B, respectively. The face panel sections are preferably formed in a lattice configuration and are made of any one of a number of synthetic materials, such as fiberglass and resin. The face panel 14 includes a periphery 16 panel which defines the shape of guitar body 2 when guitar body sections 14A and 14B are assembled.
Guitar body sections 14A and 14B are each provided with a pair of dovetail recesses 18, which are configured to accept corresponding dovetail projections 20, which are provided on the underside of guitar bridge 8.
The guitar body sections 14 are also provided with recesses 22, which are configured to accept neck section 4. The body section 14 is maintained in its proper relationship by joining corresponding mating surfaces 24 and 26, inserting neck section 4 into recesses 22 and inserting bridge projections 20 into their corresponding dovetail recesses 18 on body sections 14A and 14B.
The prior art neck section further includes dowels 30, which extend through neck wings 34 and into holes 32 in body face panels 14A and 14B. This configuration maintains the alignment of neck section 4 with respect to body 2.
At its outer end, neck 36 is provided with an angle block 38, which engages the outer end of the neck and includes a pair of elongated rectangular pins 40 received within neck slots 42. A retainer plate 44 attaches to the underside of neck 36 overlapping slots 42 to maintain pins 40 within their respective slots. A screw 46 holds retainer plate 44 in place.
Angle block 38 also includes two angled pins 48, which extend from angle block 38 in a direction opposite elongated rectangular pins 40, which is the direction of headstock 50.
The headstock 50 includes holes, not shown for receiving angled pins 48 in order to align headstock 50 with neck 36 via angle block 50. The headstock 50 also includes a recess on its underside for receiving a tensioning lever 52 pivoted about pivot shaft 54. Tensioning lever 52 includes a convex cam surface adapted to engage the angle block between pins 48 and, as will be appreciated, rotation of lever on 52 vary the distance between angle block 38 and headstock 50. Thus, the guitar strings attached to tuning machines 12 at one end and bridge section 8 at their other ends may be tensioned and detensioned as lever arm 52 is repositioned.
The body section 2 further includes an inflatable acoustic chamber, which is made up of a flexible envelope 60 within which an inflatable bladder 62 is inserted. The envelope 60 is attached to the periphery of body face panels 14 using an attachment means 72 such as a zipper, Velcro components, snaps or similar fasteners.
The prior art also discloses interchangeable bridges, such as electrical guitar bridge 8'. Electric guitar bridge 8' includes components necessary to convert the modular guitar system 1 from an acoustic mode 2 and electric mode. Electric guitar bridge 8 thus includes pickups 82, and controls 84. The electric guitar bridge 8', like acoustic guitar bridge 8 includes dovetail projections 20', which are configured to be accepted within dovetail recesses 18 on body base panels 14A and 14B respectively.
As disclosed in the '391 patent, the CHRYSALIS.TM. guitar body is comprised of two separate body grills, which are held together and in planner alignment by the guitar's bridge and a common neck joint. However, one drawback of the CHRYSALIS.TM. guitar system is that the separate body grills taught therein include both structural and acoustical braces. Accordingly, if one were to desire to modify the acoustical characteristics of the prior art CHRYSALIS.TM. guitar, one would be forced to replace both body grills in their entirety.
Another drawback of the combined structural and acoustical braces of the prior art CHRYSALIS.TM. guitar system is that the acoustical braces communicate with the structural braces along each body grill's central, longitudinal structural brace. This, although offering superior structural integrity, limits the vibrational characteristics of the acoustical braces, which adversely affects the acoustic performance of the CHRYSALIS.TM. guitar system.
Another drawback associated with the combined structural and acoustical frameworks of the prior art CHRYSALIS.TM. guitar is that in order to provide proper sound board analog acoustic compliance, the two body halves are only joined where they attach to the guitar neck and by the string bridge. Accordingly, in order to provide the necessary structural integrity, the body frame edges that are located along the central longitudinal axis of the guitar body in the assembled state, must themselves be structural frame members. This requires substantial dimensions, which further precludes the acoustical framework from freely vibrating and transmitting maximum vibrational energy to the guitar's acoustical chamber.
The prior art CHRYSALIS.TM. guitar includes a removable headstock, which rotates vertically off the neck of the guitar to allow the breakdown of the instrument as a whole. The CHRYSALIS.TM. guitar headstock utilizes a quick release mechanism, which allows for the rapid de-tensioning and re-tensioning of the guitar strings utilizing a lever mechanism. However, when the CHRYSALIS.TM. guitar strings are de-tensioned, they tend to unravel from the tuning machine posts provided on the headstock, which defeats the ability to rapidly reassemble and tune the guitar. One attempt that has been tried to overcome this problem is to add an external, add-on string clamp at the base of the headstock, which can be manually manipulated prior to de-tensioning the guitar strings using the headstock lever arm. Once the clamp is tightened, tension is maintained on each string between the clamp and their respective tuning machine posts, thus preventing unwanted string unraveling. However, this prior art solution to the problem requires a separate operator action and requires a somewhat unsightly additional mechanism on the guitars headstock.
Furthermore, the prior art CHRYSALIS.TM. guitar system, while teaching the interchangeability of necks, bridges, and headstocks, the neck body joint taught is crude and does not provide the ease of interchangeability required for commercial acceptance. Furthermore, since the neck of the prior art CHRYSALIS.TM. guitar serves more purposes than that of a normal guitar neck, the prior art CHRYSALIS.TM. guitar neck was required to be made from either solid high-modulus graphite-epoxy composite, aluminum stock or an equivalent solid structure.
Accordingly, there is a need for an improved inflatable, knock-down guitar, which overcomes the acoustic compliance, assembly, and structural deficiencies associated with prior art collapsible guitar systems, including the prior art CHRYSALIS universal guitar system.